Question: $ { \left[\begin{array}{rr}{3} & {4} \\ {1} & {-1}\end{array}\right]+\left[\begin{array}{rr}{-2} & {1} \\ {2} & {-1}\end{array}\right] = {?} } $
To find the sum of two matrices, add the corresponding items between each matrix. ${\left[\begin{array}{rr}{3}+{-2} & {4}+{1} \\ {1}+{2} & {-1}+{-1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{1} & {5} \\ {3} & {-2}\end{array}\right]}$